1. Field of the Invention
The present invention relates generally to medical devices which are used to provide access into the human body. More particularly, the present invention is directed to double lumen catheters which are used to provide infusion and/or removal of fluids from the body.
2. Description of Related Art
Central venous catheters are relatively long tubular devices which have tapered distal tips which are designed for entry into central veins to provide a dedicated route of fluid infusion into the body. The original venous catheters were single lumen devices which provided the ability to infuse a single liquid into the vein at one time. Multiple lumen catheters have since been developed which allow simultaneous introduction of two or more liquids into the vein. The dual lumen catheter is a common design which has been widely used for a number of years.
Dual lumen catheters include a tubular wall which forms a fluid conduit which typically has a circular cross-section. A single divider or lumen wall is formed inside the tubular wall to divide the circular fluid conduit into two lumens. In many instances, it is desirable that the two lumens have cross-sectional areas which are substantially equal. For example, equal lumen size is desirable in situations where the ability to provide two conduits with maximized fluid delivery rates on both lines is important.
Guidewires are commonly used to insert and locate catheters within the vascular system. The distal end of the guidewire is typically inserted into the vascular system and moved to the desired location for the catheter. The distal end of the catheter is then slipped over the guidewire and the catheter inserted into position as guided by the wire. Once the catheter is in position, the guidewire is withdrawn. It is important that the dual lumen catheter be designed to accommodate the use of guidewires. Some dual lumen catheters have included a separate lumen which is specifically designed to receive the guidewire while others have utilized one or both of the two fluid lumens as a temporary guidewire lumen. An advantage of designing and using one specific fluid lumen to receive the guidewire is that the overall size of the dual lumen catheter is minimized. This reduces the size of the wound made during insertion of the catheter into the body and reduces the wound healing time.
An important consideration in designing dual lumen catheters is to make the catheter as kink resistant as possible. In the past, kinking of the catheter during insertion into the body has been a significant problem. Accordingly, it is desirable that the cross-sectional configuration and other design features be chosen to maximize resistance to catheter kinking.
The currently available dual lumen catheters are adequate for their intended purpose. However, there is a continuing need to develop better dual lumen designs. For example, there is a continuing need to provide dual lumen catheters where the cross-sectional areas, i.e. size, of the lumens is kept substantially similar while at the same time the kink resistance and guidewire compatibility of the dual lumen catheter are improved.